A core barrel inner tube assembly that is propellable under fluid pressure to the bit end of a drill string and provide an open bypass channel for inward flow therethrough only after the latch has moved to its latch seated position.
In U.S. Pat. No. 3,120,283 to Braun there is disclosed a core barrel inner tube assembly having an overshot coupling portion retained in a position by the latches in their retracted position to prevent fluid bypass until the latches move to their seated position and thence under gravity or inward fluid pressure move to permit fluid bypass and prevent the latches moving to their retracted position until the coupling portion is retracted; and a fluidly propellable overshot assembly. Also it is old to provide a core barrel inner tube assembly that is similar to that of the second embodiment of U.S. Pat. No. 3,333,647 to Karich except that the spearpoint plug has an annular fluid seal member with a bypass channel that includes an outer port opening outwardly of the seal member and an inner port that is blocked by the latch release tube when the plug is in its inner position relative to the tube, and resilient means to urge the release tube inwardly relative to the latch body to the release position. The plug is mechanically forced to its bypass open position when the release tube moves inwardly.
U.S. Pat. No. 3,266,835 to Hall discloses a core barrel inner tube assembly fluidly propellable in any direction and includes a valve assembly connected to a spearhead and resiliently urged to a position to block fluid flow. When the inner tube assembly moves to its inner position, water pressure forces the spearhead assembly to move to open a bypass channel and allow the latches to move to a latch seated position. If the latches do not seat properly a valve is not opened and bypass is blocked. French Patent No. 2,014,485 discloses a first embodiment of a latch that has an axial outer hook portion for couplingly engaging an overshot assembly and an inner hook portion extending transversely in the opposite direction from that of the hook portion for coupling engaging a latch seat while the second embodiment has an outer hook portion for couplingly engaging an overshot assembly and an outer portion for engaging a latch seat, both of which are outwardly of the latch pivot. U.S. Pat. No. 3,701,389 to Egnelov et al also discloses some of the same structure as disclosed in the French patent. U.S. Pat. No. 1,427,268 to Dodd discloses outer latches to block outer movement of the core barrel inner tube assembly and inner latches to block inward movement when in the core collecting position.
In order to provide a core inner tube assembly that provides advantages over prior art assembles, this invention has been made.